Safety tread and method of forming the same



April 5, 1938. R. J. DE wEEs i SAFETY TREAD AND METHOD OF -FORMING THE SAME Filed June 4, 1936 man,

marsan Patented Apr. 5, 1938 U N i T i?.

STATES PATiflii-l'f OFFICE.

SAFETY TREAD AND lVIETI-IOD F FORMING THE SAME Claims.

This invention relates to new and useful improvements in safety treads, and methods of forming the same.

One object of the invention is to provide an 5 improved method of forming safety tread having insignia or indicia of a contrasting color thereon, whereby the appearance of the tread is improved and the tread is made more Visible and attractive.

An important object of the invention is to provide an improved safety tread having a portion of its surface colored, the coloring being so applied that it is protected and not exposed to the wear cn said tread.

Another object of the invention is to provide an improved tread having recesses in its surface, which recesses receive a suitable coloring, whereby the visibility of the tread, as well as the attractiveness thereof, is improved; the provision of the recesses locatingr the coloring below the plane of the wearing surface of the tread so that said coloring is not exposed to wear and is therefore, permanent.

A further object of the invention is to provide an improved method of forming a non-slip or safety tread, which consists in recessing portions of the surface of said tread, and then inserting coloring, of a contrasting nature to the color of the tread, within the recesses, whereby the co1- oring is clearly visible, and is also unexposed to wear.

Still another object of the invention is to provide an improved safety tread, which may have any desired, indicia, insignia, symbols, markings, etc., permanently applied thereto.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specication and by reference to the accompanying drawing, in which an example of the invention is shown, and wherein:

Figure l is a View of a base member and stencil, constructed in accordance with the invention,

Figure 2 is a longitudinal sectional view of the base member having the stencil overlying the same, and showing the coloring material within the grooves,

Figure 3 is a transverse, vertical sectional view of the same, and

Figure 4 is an isometric view of the completed tread applied to a stair.

In the drawing, the numeral l0 designates a metallic plate, having a general rectangular shape, which is generally known as an anti-skid or safety tread. This tread ordinarily comprises a metallic base plate having an abrasive grit, such as carbcrundum grain cast in its upper or wear-l 5 ing surface. The forming of this type of tread is accomplished by any one of a number of processes well known to the trade. The tread may be purchased on the open market, being sold under various tradenames, such as Fera1un,10 Bronzulan, Alumalun, etc. These products are formed of cast iron, steel, bronze or the like having an abrasive grit embedded therein. It is noted that the particular method of forming the plate it, so as to make the same anti-skid forms i 15 no part of the present invention, and therefore, any desired method or process may be employed.

The forward, longitudinal edge of the plate lil is formed with a ydownturned flange ll and the edge formed between the plate and ange is preferably rounded, whereby the sharp corner is eliminated. When the plate is secured to a step A, as shown in Figure 4, the flange depends from the upper surface of said step. This is the usual construction of a safety tread.

ln carrying out the invention, a plurality of transverse grooves or recesses l2 are formed in the upper, or wear surface of the plate. These grooves are preferably cast in the plate but may be formed in any desired manner. The grooves' are shown disposed in parallel relation, being spaced equi-distant from each other, but it is noted that the location of the grooves or recesses may vary. Each groove extends from the rear of the plate and terminates short of the lower edge of the flange il. However, if desired, the grooves may extend completely across the entire plate.

After the grooves, or recesses l2 are formed, the surfaces thereof are made smooth by sand blasting or machining the same. The grooves' are then coated, either partially or entirely, with the minerals, generally used in the manufacture of porcelain enamel, after which the entire tread plate is placed in a furnace at a temperature which is sufficiently high to fuse the porcelain onto the surfaces of the grooves. This baking, or application of porcelain enamel to a metallic surface is in general practice, and any suitable furnace may be employed.

The porcelain enamel may, of course, have any desired color which color is preferably contrasting to the natural color of the plate l0, whereby the general appearance of said plate is greatly improved. It is noted that the plate I0, due to the carborundum grain embedded in its surface has a dark grayish or dirty appearance, and the application of the bright colored stripes adds much to the attractiveness of the tread. The bright coloring on the tread also renders the tread more visible in dark stair Wells, thus descreasing the probability of accidents.

Since the porcelain enamel is baked, or fused on the surface of the recesses I2, said enamel is substantiallj,7 permanently applied. It is well known that porcelain enamel is subject to chipping, but this danger is avoided because the enamel, being located in the recesses, is disposed below the plane of the wearing surface of the plate I3. Therefore, the enamel is not exposed and is protected from wear, whereby it remains permanently fixed to the plate I0 throughout the life of said plate.

Any desired method may be employed in applying the coating of minerals prior to the baking operation, but it is preferable to use a metallic stencil I5. This stencil is clearly shown in Figure l, and comprises a comparatively thin sheet of metal having the same general shape as the exposed or wear surface of the plate, being formed with a curved flange I 5 along its forward longitudinal edge, which overlies the flange I I of the plate when the stencil is placed on said plate. An angular flange II is provided along the rear longitudinal edge of the stencil and this flange engages the rear edge of the plate- IG to hold the stencil in position. A plurality of transverse slots I8 are formed in the stencil and when said stencil overlies the plates the slots register with the grooves to uncover the same. The stencil is formed with flanges I8 which eX- tend throughout the length of each slot at each side thereof (Figure 2).

After the stencil is in position on the plate, the minerals, in liquid solution, are sprayed onto the stencil and, of course, pass through the slots I8 to apply a coating to the surface of the grooves. The flanges I8 adjacent the slots prevent the sprayed material from passing between the underside of the stencil and thevplate l0. The stencil is then removed from the plate and the baking operation, as above described completes the tread.

Although it is most desirable to employ the stencil in applying the coating to the recesses, it is pointed out that other methods of 4applying the same may be employed, as for instance, it would be possible to apply the coating to the recesses with a hand brush. Also, although it is preferable to apply porcelain enamel to the surface of the grooves because of its permanent nature, it is within the scope of the invention to coat the grooves with an ordinary paint, or other coloring substance. The recessing of the wear surface locates the coloring belo-w the plane of said surface, whereby the coloring is protected from the wear and thus, is permanent. The recesses or grooves are comparatively narrow; whereby substantially all of the Wear surface is maintained. It is particularly noted that the invention is not to be limited to the formation of transverse, parallel grooves, such as is shown and described, but any desired indicia, symbols, insignia, or other matter may be formed by recessing the surface accordingly. Further, although it is preferable to sand blast or machine the recesses after they have been formed by casting the plate, this step might be eliminated and the coloring material applied to the comparatively rough surface of said recesses.

What I claim and desire to secure by Letters Patent, is:

1. A safety tread including, a base member having a recess in its wear surface, and a coating of porcelain enamel within the recess, whereby the enamel is below the plane of the Wear surface and unexposed to wear.

2. The method of forming a safety tread which consists in, forming a plurality of recesses in the wear surface of a base member, placing a stencil which exposes the recesses and covers the remaining surface over said member, and applying a substantially permanent coloring substance to the surfaces of the recesses through said stencil, whereby the recesses alone are coated with the coloring.

3. The method of forming a safety tread which consists in, forming a plurality of recesses in the wear surface of a base member, placing a stencil which exposes the recesses and covers 2 the, remaining surface over said member, spraying minerals in liquid solution, into the grooves to apply a substantially permanent coating to said grooves, removing the stencil, and then applying heat to the sprayed minerals to fuse the same to the surface of the metal.

4. The method of forming a safety tread which consists in, casting a plurality of recesses in the wear surface of a base member, sand blasting the surfaces of the grooves to make the same smooth, placing a stencil which exposes the recesses and covers the remaining surface over said member, and applying a substantially permanent coloring substance to the surfaces of the recesses through said stencil, whereby the recesses alone are coated with the coloring.

5. A safety tread including, a base plate having an anti-skid wear surface and being substantially thick in cross-section to permit a plurality of transverse grooves to be formed in said wear surface, and a coating of enamel within each groove and located below the plane of the wear surface, whereby said enamel is protected from and unexposed to wear.

RUSSELL J. DE WEES. 

